Function for telling the name of a pixel format

[amigalemming]

I like to have a function that returns a human readable name for the pixel format like so:

pixelFormatName :: Juicy.DynamicImage -> String
pixelFormatName pic =
   case pic of
      Juicy.ImageY8 _ -> "Greyscale 8-bit"
      Juicy.ImageY16 _ -> "Greyscale 16-bit"
      Juicy.ImageY32 _ -> "Greyscale 32-bit"
      Juicy.ImageYF _ -> "Greyscale Floating Point"
      Juicy.ImageYA8 _ -> "Luminance + Alpha 8-bit"
      Juicy.ImageYA16 _ -> "Luminance + Alpha 16-bit"
      Juicy.ImageRGB8 _ -> "RGB 8-bit"
      Juicy.ImageRGB16 _ -> "RGB 16-bit"
      Juicy.ImageRGBA8 _ -> "RGBA 8-bit"
      Juicy.ImageRGBA16 _ -> "RGBA 16-bit"
      Juicy.ImageYCbCr8 _ -> "YCbCr 8-bit"
      Juicy.ImageCMYK8 _ -> "CMYK 8-bit"
      Juicy.ImageCMYK16 _ -> "CMYK 16-bit"
      Juicy.ImageRGBF _ -> "RGB Floating Point"

undefinedImage :: Juicy.Image a
undefinedImage = error "no image"

I want to use this to tell people that I encountered a format that I do not support. I propose to add also undefinedImage in order to tell a format that I support. I can write this function on my own but I have to adapt it to every future extension of the DynamicImage enumeration that I do not support.